CN115229175A

CN115229175A - 3D printing forming method of steel particle reinforced tin-based composite material

Info

Publication number: CN115229175A
Application number: CN202210912998.7A
Authority: CN
Inventors: 汪炳叔; 詹博文; 丁丁
Original assignee: Fuzhou University
Current assignee: Fuzhou University
Priority date: 2022-07-31
Filing date: 2022-07-31
Publication date: 2022-10-25
Anticipated expiration: 2042-07-31
Also published as: CN115229175B

Abstract

The invention discloses a 3D printing forming method of a steel particle reinforced tin-based composite material, which comprises the following steps: mixing the two kinds of steel and tin powder by using an automatic powder mixer, wherein the mixing time is t1; drying the mixed powder in vacuum for T2 at the drying temperature of T1; importing the STL file of the part to be printed into slicing software, setting process parameters, and slicing; and (3) placing the mixed powder into a 3D printer, and printing and forming according to a slicing program. The invention provides a 3D printing forming method of a steel particle reinforced tin-based composite material with high strength and good reliability.

Description

3D printing forming method of steel particle reinforced tin-based composite material

Technical Field

The invention belongs to the field of additive manufacturing, and relates to a 3D printing forming method of a steel particle reinforced tin-based composite material.

Background

Tin is an indispensable overload protection material as a low-melting-point metal, and has wide application in the fields of high-temperature explosion prevention, circuit protection and the like. The operation sensitivity of the fuse protector made of the metal material needs to be improved by mechanical force formed by an additional spring and the like, and further, the metal itself needs to have certain mechanical strength; however, tin has low strength and is difficult to bear high-strength load, and in order to solve the problem, methods of alloying and particle reinforcement are proposed to improve the strength of tin alloy itself, so that the tin alloy can be widely applied to circuit protection components such as fuses, fuses and the like.

In the prior art, the strength of tin alloy strengthened by alloying a small amount of other metals is not too high, and the tin alloy can not meet the application occasions with part of high load; the particle reinforced tin-based composite material prepared by adopting the traditional modes of dipping, casting, deposition and the like has the defects of poor forming effect and unstable mechanical property.

In view of the above, the invention provides a 3D printing forming method of a steel particle reinforced pure tin composite material, and a formed sample obtained by the method has the advantages of high strength and strong reliability.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a forming method of a tin-based composite material with higher strength and good reliability.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a selective laser melting forming method of a steel particle reinforced pure tin composite material comprises the following steps:

s1: mixing steel powder and tin powder, wherein the steel powder accounts for 5-15% of the mass of the tin powder; (ii) a

S2: vacuum drying the mixed powder;

s3: importing the STL file of the part to be printed into slicing software, setting process parameters, and slicing;

s4: and placing the dried powder into a 3D printer, and printing and forming according to a slicing program.

Preferably, in step S1: and the two kinds of powder are mixed for 4 hours by using a mechanical powder mixer.

Preferably, in step S2, the powder is vacuum dried for 4 hours; the vacuum drying temperature is 50 ℃.

Preferably, in step S4: in the set printing parameters, the laser power is 80W, the scanning speed is 500mm/s, the scanning distance is 0.05mm, and the printing layer thickness is 0.03mm.

Preferably, step S3 further comprises: if the included angle between the tangent line of the bottom surface of the part and the plane of the substrate is more than 70 degrees, a mesh support needs to be added for assisting printing.

Preferably, the steel powder may be carbon steel such as 45 steel, 20 steel, stainless steel, or other alloy steel.

Preferably, the steel powder particle size is 1-15um.

Preferably, the tin powder is 99.99% pure tin powder.

Preferably, the tin powder particle size is 15-55um.

Preferably, the vacuum drying can be realized by a vacuum drying box or the like.

Preferably, the slicing software is magics slicing software.

Preferably, the 3D printer is a selective laser melting printer SLM-100.

Compared with the prior art, the embodiment of the invention has the following beneficial effects:

according to the invention, the mixed powder is printed layer by a 3D printing and forming method, so that the steel particles can be easily and uniformly distributed in the tin matrix, and the problem that the steel particles cannot be uniformly distributed in the tin matrix in the traditional casting mode is solved.

Drawings

FIG. 1 is a schematic flow diagram of a 3D printing forming method of a steel particle reinforced pure tin composite of example 1;

fig. 2 is a schematic flow diagram of a 3D printing forming method of the steel particle reinforced pure tin composite material of example 2;

fig. 3 is a schematic flow chart of a 3D printing forming method of the steel particle reinforced pure tin composite material of example 13.

Detailed Description

In order to facilitate an understanding of the invention, the invention is described in more detail below with reference to the accompanying drawings and specific examples. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

The composite material comprises common particle reinforced composite materials such as carbide, nitride, graphite, steel particles and the like, and the wettability between the composite material and a tin melt is poor, so that the steel particles are difficult to be uniformly distributed in a tin matrix by adopting the forming modes of the traditional particle reinforced composite materials such as dipping, casting, deposition and the like, and in a formed sample, the agglomeration phenomenon of the steel particles is obvious, so that the mechanical property of the composite material is seriously reduced. In order to solve the problem, the invention provides a 3D printing forming mode of selective laser melting to realize high-strength combination of the steel particles and the tin matrix.

According to the phase diagram, during the solidification of the tin steel, a small amount of intermetallic compounds are formed by chemical reaction at 513 ℃. Through experiment and theoretical analysis, discover through the sample of election district laser melting with steel tin mixed powder sintering shaping, not only can make steel granule evenly distributed in the tin base member through the stirring effect of the little molten bath of laser, and simultaneously, because of the election district laser melting in-process, local high temperature in the molten bath, intermetallic compound that can make steel tin produce encircles and distributes around the steel granule, the infiltration nature between steel granule and the tin solution has been improved, thereby the bonding strength at steel tin interface has been strengthened, and then the clearance that particle and base member lead to because of the thermal expansion coefficient difference has been reduced, the holistic mechanical properties of combined material has been strengthened. The following further describes embodiments of the present invention with reference to the drawings.

Example 1

Embodiment 1 provides a 3D printing forming method of steel particle reinforced pure tin. Referring to fig. 1, fig. 1 is a schematic flow chart of an embodiment of a 3D printing and forming method of steel particle reinforced pure tin according to the present invention, and as shown in fig. 1, the 3D printing and forming method of steel particle reinforced pure tin includes the following steps:

s11: adding 5% of steel powder in mass fraction into tin powder, and mixing the two kinds of powder.

The steel powder is 316 stainless steel powder with the grain size of 15-55um; the tin powder is pure tin powder, and the particle size is about 55um. The steel powder added is 5% by mass of the tin powder. The powder mixing mode can adopt a manual or automatic powder mixing machine. The automatic powder mixer can be a special 3D printing powder mixer. Considering that the steel particles can be uniformly distributed in the tin powder, the rotating speed of the automatic powder mixing machine needs to be set to be 20 r/min, and the powder mixing time is 4h.

S12: and (4) drying the mixed powder in vacuum.

The stoving of mixed powder can be realized through the supporting vacuum drying case of 3D printer. Considering that air and moisture mixed in the powder can cause adverse effects on a formed sample in the printing process, the powder needs to be dried in vacuum before printing, the moisture and the air mixed in the powder are removed, and the drying time is 4h. Meanwhile, considering that the recrystallization temperature of tin is low, in order to maintain the inherent state of tin powder, the drying temperature is set to be 40-50 ℃.

S13: and importing the STL file of the rod-shaped model into slicing software, setting process parameters and slicing.

Specifically, a three-dimensional model of the bar is converted into an STL file format, and the STL file format is imported into slicing software for opening, wherein the slicing software is magics; preferably, when the included angle between the tangent line of the bottom surface of the bar and the plane of the substrate is less than 70 degrees, the reticular support is added to assist printing. Preferably, the printing parameters of the support are as follows: the laser power is 60-80W, the scanning speed is 800-2000mm/s, and the scanning interval is 0.05mm. Preferably, the printing parameters of the part are as follows: the laser power was 80W, the scanning speed was 500mm/s, the scanning pitch was 0.05mm, and the print layer thickness was 0.03mm.

In fact, it has been found through experiments that the input of too much or too little energy density during the printing forming process can cause the forming effect to be poor. The main reason is that the processing temperature is higher than the boiling point of tin due to over-high energy, so that part of tin is vaporized and cannot be discharged in time, and a large amount of air holes are formed in a matrix after solidification; meanwhile, due to the fact that the temperature gradient in the molten pool is too large due to too high energy, the generated thermal residual stress is larger than the adhesive force between the lower printing pieces, and the local warping of the printing pieces is serious. Too low an energy density may result in insufficient overlap between adjacent melt pools in the same print plane, thereby creating a large number of fusion gaps between the two melt pools. Considering that the scanning speed is slow and the fluidity of the melt in the molten pool is high, when the included angle between the tangent line of the bottom surface of the bar and the plane of the substrate is less than 70 degrees, grid support is added to assist printing so as to ensure the formed shape.

S14: and (4) placing the steel-tin mixed powder into a 3D printer, and printing and forming according to a slicing program.

In the embodiment, 5% of steel powder in mass fraction is added into the tin powder, and 3D printing forming is performed, so that after the steel-tin mixed powder is printed and formed layer by layer, steel particles can be distributed in a tin matrix more uniformly and are well combined with the matrix. After subsequent processing into tensile samples, the tensile strength is measured to be stably distributed at about 85mpa, and the elongation is measured to be about 12%. Compared with pure tin, the tensile strength is improved by 466 percent.

Example 2

Referring to fig. 2, fig. 2 is a schematic flow chart illustrating a 3D printing and forming method of a steel particle reinforced tin-based composite material according to another embodiment of the present invention. As shown in fig. 2, the 3D printing forming method of steel particle reinforced pure tin in this embodiment includes the following steps:

s21: adding 10% of steel powder in mass fraction into tin powder, and mixing the two kinds of powder.

The steel powder is 316 stainless steel powder with the grain size of 15-55um; the tin powder is pure tin powder, and the particle size is about 55um. The steel powder added is 10% by mass of the tin powder. The powder mixing mode can adopt a manual or automatic powder mixing machine. The automatic powder mixer can be a special 3D printing powder mixer. Considering that the steel particles can be uniformly distributed in the tin powder, the rotating speed of the automatic powder mixing machine needs to be set to be 20 revolutions per minute, and the powder mixing time is 4 hours.

S22: and (4) drying the mixed powder in vacuum.

S23: and importing the STL file of the rod-shaped model into slicing software, setting the process parameters, and slicing.

Specifically, converting the three-dimensional model of the bar into an STL file format, and importing the bar into slicing software for opening, wherein the slicing software is magics; preferably, when the included angle between the bottom surface tangent line of the bar and the plane of the substrate is less than 70 degrees, the reticular support is added to assist printing. Preferably, the printing parameters of the support are as follows: the laser power is 60-80W, the scanning speed is 800-2000mm/s, and the scanning distance is 0.05mm. Preferably, the printing parameters of the part are as follows: the laser power was 80W, the scanning speed was 500mm/s, the scanning pitch was 0.05mm, and the print layer thickness was 0.03mm.

S24: and (3) placing the steel-tin mixed powder into a 3D printer, and printing and forming according to a slicing program.

In this embodiment, 10% by mass of the steel powder is added to the tin powder, and the steel powder is subjected to 3D printing and forming, so that after the steel-tin mixed powder is subjected to layer-by-layer printing and forming, the steel particles can be distributed in the tin matrix more uniformly and can be well combined with the matrix. After subsequent processing into tensile samples, the tensile strength is measured to be stably distributed at about 120mpa, and the elongation is measured to be about 8%. Compared with pure tin, the tensile strength is improved by 700 percent.

Example 3

Referring to fig. 3, fig. 3 is a schematic flow chart of another embodiment of the 3D printing and forming method of the steel particle reinforced tin-based composite material of the present invention. As shown in fig. 3, the 3D printing forming method of steel particle reinforced pure tin in this embodiment includes the following steps:

s31: adding 15% of steel powder in mass fraction into tin powder, and mixing the two powders.

The steel powder is 316 stainless steel powder with the grain size of 15-55um; the tin powder is pure tin powder, and the particle size is about 55um. The steel powder added was 15% by mass of the tin powder. The powder mixing mode can adopt a manual or automatic powder mixing machine. The automatic powder mixer can be a special 3D printing powder mixer. Considering that the steel particles can be uniformly distributed in the tin powder, the rotating speed of the automatic powder mixing machine needs to be set to be 20 r/min, and the powder mixing time is 4h.

S32: and (4) drying the mixed powder in vacuum.

S33: and importing the STL file of the rod-shaped model into slicing software, setting process parameters, and slicing.

Specifically, a three-dimensional model of the bar is converted into an STL file format, and the STL file format is imported into slicing software for opening, wherein the slicing software is magics; preferably, when the included angle between the tangent line of the bottom surface of the bar and the plane of the substrate is less than 70 degrees, the reticular support is added to assist printing. Preferably, the printing parameters of the support are as follows: the laser power is 60-80W, the scanning speed is 800-2000mm/s, and the scanning interval is 0.05mm. Preferably, the printing parameters of the part are as follows: the laser power was 60W, the scanning speed was 500mm/s, the scanning pitch was 0.05mm, and the print layer thickness was 0.03mm.

In fact, it has been found through experiments that an increase in the steel content leads to a reduction in the forming window, mainly because the increase in the steel content exacerbates the residual stress of deformation caused by the difference in the thermal expansion coefficients of the steel and tin, and the high energy input causes the part to warp severely during printing, in addition to the residual stress of heat caused by the large temperature gradient in the molten bath. Considering that the scanning speed is slow and the fluidity of the melt in the molten pool is large, when the included angle between the tangent line of the bottom surface of the bar and the plane of the substrate is less than 70 degrees, grid support is added to assist printing so as to ensure the shape after forming.

S34: and (3) placing the steel-tin mixed powder into a 3D printer, and printing and forming according to a slicing program.

In the embodiment, 15% of steel powder in mass fraction is added into tin powder, and 3D printing forming is performed, so that after the steel-tin mixed powder is printed and formed layer by layer, steel particles can be distributed in a tin matrix more uniformly, but a small amount of agglomeration phenomenon exists. After subsequent processing into tensile test sample, the tensile strength distribution is measured to be between 120 and 150 MPa.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and these modifications or substitutions do not depart from the spirit of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A3D printing forming method of a steel particle reinforced tin-based composite material is characterized by comprising the following steps:

s1: mixing the steel powder and the tin powder, and then drying in vacuum;

s2: and placing the dried powder in a 3D printer, and printing and forming according to the printing parameters of the part to be printed.

2. The 3D printing forming method of steel particle reinforced tin-based composite material as claimed in claim 1, wherein the steel powder in step S1 is 45 steel, 20 steel or stainless steel, and the steel powder particle size is 1-15um.

3. 3D printing forming method of steel particle reinforced tin based composite material according to claim 1, characterized in that in step S1 the tin powder is 99.99% pure tin powder, the tin powder particle size is 15-55um.

4. A method for 3D printing and forming of a steel particle reinforced tin based composite material according to claim 1, characterised in that the mixing is with a mechanical powder mixer for 4 hours.

5. The 3D printing forming method for the steel particle reinforced tin-based composite material as claimed in claim 1, wherein the time of vacuum drying in the step S2 is 4h; the temperature for vacuum drying was 50 ℃.

6. The 3D printing forming method of the steel particle reinforced tin-based composite material as claimed in claim 1, wherein the laser power of the 3D printer in the step S2 is 80W, the scanning speed is 500mm/S, the scanning interval is 0.05mm, and the printing layer thickness is 0.03mm.